In illumination field, white LED sources are developed to be a matured technology, the most widely used while LED source is applied with a blue LED combined with phosphor, which is stimulated to emit yellow light, the blue light and the yellow light mix to get a white chromatic spectrum.
As the LED sources are small in size, if high luminous flux and high power are needed, it has to provide many LED sources, a traditional method is to use single white sources fixed in a same substrate to provide an LED module with enough luminous flux, this method has complete production chains, the technique thereof is relative matured, however, unavoidable, every single LED source needs individual package process, it means that every single LED source needs a complete manufacturing of bonding, potting, coating and packing, although it has made a production on a large scale, the package material and manufacturing during are unavoidable.
Aiming at this problem, existing technology is applied with COB (chip-on-board) method, that is to say, directly fixing the LED chips on the substrate, getting the LED module without packing, then coating the entire LED module with phosphor, finally packing the substrate with many LED sources, it reduces the material cost and manufacturing during of every single LED source, thus improving the manufacturing cost and during of a LED module. however, according to the character of the LED sources, light photon emits to the free space from the semiconductor chip after multiple total reflections and/or refractions, the top and sides of the chip send luminous flux, so the best condition is that the phosphor is evenly coating on every shiny side, thus ensuring the consistency of the photochromic of the mixing light in the emit angle; but in the LED module applied with COB method, when coating the phosphor, it is hard to obtain the consistency of the geometry of the phosphor of every single LED source when in high efficiency and large scale coating, resulting in inconsistency of the photochromic of LED module in different emit angles, thus reducing the quality of white light illumination, even resulting in uncomfortable, especially in non-planar substrate, it is more hard to guarantee an even coating; in case to efficiently coating on every LED chip, it resumes much phosphor to coat the sides of the LED chips, thus resulting in a waste of phosphor.